1. Field of the Invention
The present invention relates to semiconductor memory and switching devices and, more particularly, to non-volatile semiconductor memory and switching devices employing a Schottky barrier junction and a dual dielectric system for entrapping charges adjacent thereto. Trapped charges cause the Schottky barrier junction to vary in conductivity characteristics between that of a conventional diode (OFF) and that of a simple ohmic contact (ON) in accordance with the magnitude of the trapped charge.
2. Description of the Prior Art
Need has existed for some time for semiconductor memory and switching devices which are simple in design and capable of manufacture in compact arrays, and which provide memory and switching capability that permits rapid, non-destructive data readout, as required for certain switching and programmed read only memory (PROM) applications.
The prior art is replete with various types of semiconductor memory and switching devices susceptible to configuration in array fashion. One such device is the insulated gate field effect transistor made alterable by using layers of different dielectric insulating material capable of storing or capturing electron charges when a voltage exceeding a certain critical value is applied to the gate. Examples of such prior art may be found by reference to U.S. Pat. No. 3,882,469 to W. M. Gosney, Jr. entitled "Non-volatile Variable Threshold Memory Cell" and to U.S. Pat. No. 3,649,884 to Y. Haneta entitled "Field Effect Semiconductor Device with Memory Function". An example of a non-volatile diode cross point memory array using dual layered dielectric and a diffused semiconductor structure may be found by reference to U.S. Pat. No. 3,838,405 to Arnett et al. A non-volatile memory cell using the dual layered dielectric with Schottky barrier diode has also been employed in the prior art. An example of the latter arrangement may be found in U.S. Pat. No. 4,010,482 to Abbas et al.
The difficulty with the above and other non-volatile memory cell arrangements, resides in the fact that they are difficult to make and fail to lend themselves to fabrication at sufficiently high densities. Accordingly, need still exists for improved semiconductor memory and switching devices exhibiting the characteristics of being non-volatile and permitting non-destructive readout, and yet are simple to make and easy to integrate into dense arrays.